Method for determining permeability alignment in a formation



May 4, 1965 J. M. PALMER 3,181,608 g METHOD FOR DETERMINING PERMEABILITYALIGNMENT IN A FORMATION Filed Aug. ll, 1961 4 Sheets-Sheet l HISATTORNEY May 4, 1965 J. M. PALMER 3,181,608

METHOD FOR DETERMINING PERMEABILITY ALIGNMENT IN A FORMATION Filed Aug.ll, 1961 4 Sheets-Sheet 2 FIG.5

INVENTOR.'

J. M. PALMER BY: Z

HIS ATTORNEY J. M. PALMER 3,181,608

METHOD FOR DETERMINING PERMEABILITY ALIGNMENT IN A FORMATION May 4, 1965Filed Aug. 11. 1961 4 Sheets-Sheet 5 INVENTORI J. M. PALMER BY@- mff my'HIS ATTORNEY May 4 1965 J. M. PALMER 3,181,608

METHOD FOR DETERMINING PERMEABILITY ALIGNMENT IN A FORMATION Filed Aug.ll, 1961 4 Sheets-Sheet 4 INVENTOR:

J. M. PALMER BYyWf/@'q/ HIS ATTORNEY United States Patent @dice3,181,698 Patented May 4, 1965 3,181,603 ll/IETHOD FUR DETERMINENGPERMEABILITY ALIGNMENT IN A FORMATEON John M. Palmer, Midland, Tex.,assigner to Shell Oil Company, New York, N.Y., a corporation of DelawareFiled Aug. 11, 1961, Ser. No. 130,302 3 Claims. (Cl. 166-4) Thisinvention pertains to drilling well equipment and more particularly to amethod which determines the directi-on of permeability alignment in anearth formation penetrated by a borehole and provides a method forperforating the formation at any desired angle to the direction ofpermeability alignment, and for directionally treating the formation;all of these services to be accomplished with one run of the tool.

In oil wells drilled in carbonate formations it is often necessary toperforate the formations and treat them by acidizing or fracturing toproduce the petroleum in place. In order to increase the effectivedrainage radius of the borehole to the maximum extent the perforationsand subsequent treatment should be at right angles to any preferreddirection of permeability alignment in the formation. lt would bepossible, under favorable circumstances, to obtain cores during thedrilling operations and investigate the cores to determine thepermeability alignment of the formation. However, the results of thisprocedure have not generally been satisfactory due to the expense anddifficulty of obtaining cores and the problems associated withdetermining the azimuth of the core in relation to the formation.

In addition to the above described coring operation various loggingmethods are in use to determine the apparent porosity of the variousformations penetrated by a borehole. While the use of various loggingmethods provides some information as to the apparent porosity of theformation they do not supply information as to the direction of lateralpermeability variations in the formation.

The availability of information that indicates the apparent direction ofpermeability alignment in a formation would be useful in many elds ofpetroleum operations. For example, the information could be used topredict formation permeability trends, and also to indicate the mostefficient disposition of input and withdrawal Wells in a secondaryrecovery operation.

Accordingly, it is the principal object of this invention to provide amethod capable of determining the preferred direction of permeabilityalignment that may exist in a formation penetrated by a welloore.

A further object of the present invention is to provide a method whichemploys an apparatus that seals off from overlying and underlying layersa formation whose permeability alignment is to be determined and thenforces fluid into the formation in a plurality of directions todetermine the preferred direction of permeability alignment of theformation.

A still further object of the present invention is to pro- Vide a methodfor determining the directional permeability of a formation and thenperforating and treatlng the formation in a direction normal to thepreferred direction of permeability alignment, all being accomplishedwith a single run of the tool in the wellbore.

The above objects and advantages of this invention are achieved byproviding an apparatus having two expandable packing members spacedalong a tubular support member. The packing members are disposed to sealoff the formation to be tested when pressurized fluid is supplied to theapparatus to expand the packing members. A flexible expandable tubularmember is attached to the packing members by a fluid tight seal andprovided with at least one row of longitudinal holes or openings.Preferably two or more rows of holes that are spaced on diametricallyopposite sides of the tubular member are utilized. A series ofperforating charges are mounted on the outer surface of the flexibletubular member, and aligned normal to a plane passing through the axisof the holes.

The method of this invention consists of lowering the apparatus into theborehole and disposing it opposite the formation to be tested. Next,fluid is pumped into the tubular support member to expand both thepacking members and the flexible tubular member into contact with theformation. After the members have been expanded the pressurized fluidwill llow through the holes formed in the ilexible tubular member andinto the formation. The rate of flow and the pumping pressure of thefluid will be related to the permeability of the formation intervalopposite the perforations in the packer. Thus, by determining thedirection for which the largest Volume of fluid is injected per pound ofpump pressure, the directional alignment of maximum permeability of theformation will be determined. Once this direction is determined theformation can be perforated normal thereto (or at any other angle) byutilizing the perforating charges disposed on the outer surface of theflexible tubular member.

The above objects and advantages will be more easily understood from thefollowing detailed description of a preferred embodiment when taken inconjunction with the attached drawings, in which:

FIGURE l is an elevation view of an apparatus oonstructed in accordancewith this invention and disposed in a borehole;

FIGURE 2 is the vertical section of the apparatus shown in FIGURE 1 withthe packing members and the flexible tubular member expanded intocontact with the formation;

FIGURE 3 is a horizontal section taken along the line 3 3 of FIGURE 2and showing the wall construction of the flexible tubular member;

FIGURE 4 is an enlarged elevation view of a portion of the expandiblesleeve shown in FIGURE l.

FlGURE 5 is a vertical section of the differential pressure valvedisposed at the lower end of the apparatus shown in FIGURE l;

FIGURE 6 is a perspective View of the surface equipment used to inflatethe sleeve shown in FIGURE l; and

FIGURE 7 is a representative chart of a recording obtained whenoperating this invention.

Referring now to FIGURE l, there is shown an apparatus 11 constructed inaccordance with this invention disposed in a borehole 1d. Thepermeability testing apparatus 11 may be lowered into the borehole byvarious means, for example, a tubing string 12 may be used. The -tubingstring 12 in addition to providing a means for lowering the permeabilitytesting apparatus into a borehole provides means for rotating the toolafter it is lowered into the borehole. Of course, the use of a tubingstring also provides a simple means by which fluid may be pumped intothe interior of the packing members and the flexible tubing member toexpand them into contact with the formation. The permeability testingapparatus is centered in the borehole by means of a plurality ofcircumferentially spaced upper centering springs 13 and lower centeringsprings 14 whose construction and use is well known in the art. Anexpandable packing member 15 is disposed at the upper end of the tooland has its collar 17 secured in a fluid tight manner to the tubularsupport Ztl of the permeability testing apparatus. A semilar expandablepacking member 16 is secured to the lower end of the tubular member Zt)by means of a collar 1S. The packing members may be attached to thecollars by various means as by molding the flexible packing mem-Velongated exible elastic sleeve member 21 is coupled or sealed atopposite ends to the expanding packing members 15 and 16. The sealbetween the elastic sleeve 21 and the packing member may be effected byany means desired or the packing members and the sleeve may be moldedfrom one piece of flexible elastic material, for example, rubber or thelike. At least two vertical rows of holes or openings 22 are formed inthe center portion of the elastic sleeve 21. As is seen in FIGURE 3 andFIGURE 4, several vertical rows of small size openings 22 are formed oneach side of the sleeve 21 and disposed on diametrically opposite sidesof the sleeve 21. The rows -of holes are preferably circumferentiallyspaced over the surface of the sleeve 21 to include an angle A ofapproximately 45 degrees. The two collars 17 and 18 of the packingmembers are attached to a tubular member 26 by any desired means such asthreaded connections or the like. The tubular member 26 maintains theproper alignment between the collars in additionV to providing thenecessary support for the packing members and sleeve 21. A series ofopenings 23 are formed in the tubular member 26 between the two packingmembers 15 and 16 to provide a means by which uid may be pumped into theamanece readily lowered into a wellbore by means of the tubing string12. The differential pressure valve 30 will permit the pressure betweenthe interior of the tool and the borehole to equalize as the apparatusis lowered until it is located at the elevation of thel formation 10 tobe tested. When located at the proper position luid is pumped into theinterior of the apparatusV by means of the tubing Y string 12, thetubular support member 20 and 26. As'the pressurized fluid is introducedinto the interior of the testing member at a rate higher than the normalcirculating rate it will'close the differential pressure valve 30, andwill expand the packing members 15 and 16 into contact Vwith the wall ofthe borehole, thus sealing olf the formation 19. Continued pumping at apressure greater than that which will allow the differential valve toopen again will then force the fluid out through the openings v is foundthat results in the maximum flow of fluid with interior of the flexiblesleeve 21 and the two packing members to expand them into contact withthe formation. As shown in FIGURE 4 the openings 22 in the sleeve 21 arepreferably of small diameters and connected by a network of shallowchannels 27`molded or otherwise formed in the outer surface of thesleeve 21. The channels 27 are on the order of G inch deep and insuremaximum access of the fluid pumped into'sleeve to the porous portions ofthe formations. The openings 22 must be maintained small to restrict thevolume of fluid pumped into the formations to permit operation of thedifferential valve 30 as explained below.

Disposed at the lower end of the apparatus shown in FIGURE l is adifferential pressure valve 3) designed to open whenever the pressuredifferential between the borehole 10 and the interior of thepermeability testing tool exceeds certain limits. The construction ofthis valve is shown in greater detail in FIGURE 5. Y

Referring now to FIGURES 5, there is shown the valve 30 having a valvebody 31 with a piston 32 disposed for movement therein. The piston isurged in an upward direction by means of a compression spring 33 held inposition by an end cap 35 that threads into the lower end of the valvebody 31. The end cap 35 is provided with a series of openings 34 inorder that the bottom of the piston 32 will be subject to the pressureof the uid present in the borehole 10. A vertical member or post 36extends from the upper surface of the piston and is disposed to lift aball member 37 from its seat 38 whenever the piston travels in an upwarddirection. The piston is provided with a series of ports or openings 39which are y aligned with ports v40 formed in the valve body l'when thepiston is in its upper position. From the above description it can beappreciated that normally the piston 32 will be urged to its upperposition by the spring 33 thus aligning the ports 39 and 40 to permitfree ilow of fluid between the borehole 10 and the interior of thesleeve 21. Whenever the pressure on the top of the piston exceeds thecombined force of the spring 33 and the pressure of borehole fluidacting on the bottom of the piston, the piston will beV forced in adownwardly direction permitting the ball to seat on the surface 38. Thiswill close off the communication between the interior of the sleevemember 21 and the borehole as a result of the ports 39 and 40 moving outof alignment.

From the above description it can be readily appreciated that there hasbeen provided an apparatus which may be the minimum pump pressure, whichwill be the direction of preferred permeability alignment within theformation interval tested. Once the direction of preferred permeabilityalignment is determined the azimuth may be recorded using an azimuthdetecting means 24 located at the top of the apparatus. A suitableazimuth detecting and recording means is shown in Patent 2,659,160. Theformation may be kperforated normal to this direction (or in any otherdesired direction) as described below.

Again referring to FIGURE 3, there is shown thickened sections 50 formedin the wall of the sleeve member 21. The thickened sections are disposedon diametrically opposite sides of the sleeve member 21 in a plane atright angles to the openings 22. Disposed within the thickened section50 are perforating charge supporting members 51. These supportingmembers are cup shaped chambers for supporting shaped charges as shownin FIGURE 1, and may be molded in the member 21 when it is formed or maybe fastened therein by any well known means. TheA cup shaped members 51are disposed to hold a shaped jet perforating charge 52. A suitabletiring circuit 54 is also disposed in the thickened section 50 andcouples all of the perforating charges together and to a tiring devicelocated just above the tool, and detonated by some method such asdropping a bar into the tubing from the surface. For example the ringcircuit and actuating means shown in Patent No. 2,154,859 may be used.After the preferred direction of permeability alignment of the formationhas been determined, the formation may be perforated at right angles tothis direction (or in any other direction) by merely energizing thefiring circuit 54 described above. This will cause the perforatingcharges to fire outward into the formation to perforate it. Theapparatus may then be repositioned in the borehole and the formationtreated by acidizing or fluid fracturing in the desired directionthrough the openings 22. Y

By disposing the perforating charges in the outer surface of the sleevemember 21 'and then expanding the member firmly against the formationwall, more efficient perforating can be accomplished since the chargeswill not be required to travel through the borehole fluid before theyreach the formation. The disposition` of the perforatingl chargesdirectly on the sleeve member permits the determination of thepermeability alignment, and the perforating and treating of a formationinterval with a single trip of the apparatus into the borehole. In somecases it may not be desired to perforate the formation but onlydetermine its permeability alignment and treat in an appropriate manner.In these cases the same apparatus may be used and the perforatingcharges omitted or an apparatus may be constructed Without provision forthe perforating changes.

Referring now to FIGURE 6, there is shown a perspective View of thesurface equipment for pumping fluid into the elongated member to expandit as well as the equipment required to measure the ow rate and pressureof the fluid being pumped. The tubing 12 that is used to support theinstrument in the borehole is held in position by the use of ordinaryslips '70 and the opening in the rotary table 71. In addition, therotary table may have a reference line 72 incribed thereon to permit thedownhole tool to be positioned in a plurality of oriented directionsaround a periphery of the borehole. The pipe 12 is raised and lowered inthe borehole by the derrick 73 of a customary drilling rig.

The uid for expanding the downbore tool is applied by the mud pump 74through a pipe '75 that is coupled to the end of the tubing string 12 bymeans of a swivel joint 76. Disposed in the pipe 75 is a flowmeter 77and recording pressure gage 78. The fiowmeter 77 should measure the rateof ow in units of time, for example, in gallons per hour. An alternativeto the use of the iowmeter would beto count the strokes of the mud pump75 and convert the strokes to volume. The recording pressure gage 78 ispreferably of the type which utilizes a circular chart that is driven bya clockwork mechanism.

Referring now to FIGURE 7, there is shown the sample chart from therecording pressure gage '78 of FIGURE 6 with the tlow rates notedthereon. From the chart of FIGURE 7 it is seen that the downhole toolwas rotating in approximate 45 degree increments to survey the entireperiphery of the borehole at the location of the formation being tested.Referring now to a particular signal 6l) appearing on the chart ofFIGURE 7, the low pressure recordings 61 and 62 reflect the pumppressures when the packers and 16 of FIGURE 1 are deflated andcirculation of the fluid is primarily through the differential pressurevalve 30, located at the bottom of the tool. The peak reading 63reflects the pressures required to close the diiferential valve andinflate and packer against the borehole. The steady pressure readings 66reflect the pressure required to pump fluid into the formation beingtested after the dierential valve closes.

The rate of pumping in gallons per hour is recorded on the chart recordfor each directional setting of the downhole tool. The rate of flow incombination With the steady pressure provide a rati-o of gallons pumpedper pound of pumping pressure. This ratio provides a relative measure ofthe permeability of `the formation for each of the individualdirectional settings of the downhole tool. Thus, it is seen that for thesignal 60 the ratio between the rate of flow and the pressure, i.e.,1100/ 1000 is equal to 1.10 While for the signal 64 the ratio isapproximately 125 0/ 590 or 2.12. Accordingly, for the particularformation tested the porosity in the direction indicated by the signals64 and 65 is approximately twice the porosity of the formation in adirection normal to this.

If desired additional directional readings may be obtained although inmost cases one reading for every 45 increment is sufiicient.Furthermore, it is normally only necessary to take readings throughsince the instrument is provided with tWo sets of openings in theflexible sleeve 21.

While only a single embodiment of this invention has been described indetail, many modications may be made within its broad spirit and scope.Accordingly this invention should not be limited to the detailsdescribed for the purpose of illustration.

I claim as my invention:

l. A method for determining the alignment of lateral permeabilityvariations in a formation penetrated by a borehole comprising: sealingolf a section of the borehole including at least a portion of saidformation; injecting a fluid into the sealed off portion of theformation in controlled directions; detecting the azimuth of thedirection in which the iluid is injected; rotating the point at whichthe Huid is injected in increments of about 45 to attempt injectionaround the entire periphery of the borehole and recording the rate ofinjection and corresponding pressure as the uid is injected in eachdirection increment.

2. A method of directionally perforating a formation penetrated by aborehole comprising: sealing olf a section 'of the borehole including atleast a portion of said formation; injecting a uid into the formation ina controlled and measured direction, rotating the direction of theinjection of said fluid in increments to include the entire periphery ofthe borehole; detecting the rate of injection and pressure of the iiuidin each of said directional increments to determine the direction ofmaximum rate and minimum pressure; orienting a perforating device in adirection related to the direction of maximum llow and minimum pressureand perforating the formation in the oriented direction.

3. A method for determining directional permeability alignment andtreating a formation, said method comprising: sealing off a section of aborehole including at least a portion of said formation; injecting ailuid into the formation in a controlled and measured direction;rotating the direction of injection of said iiuid increments to includethe entire periphery of the borehole; detecting the rate of injectionand the pressure of the iluid in each of said directional increments todetermine the direction of maximum rate and minimum pressure; orientinga perforating device in a direction related to the direction of maximumflow and minimum pressure, perforating the formation in `the orienteddirection and then injecting a treating iiuid into the formation in saidoriented direction.

References Cited by the Examiner UNITED STATES PATENTS 2,019,418 10/35Lang 166-185 2,301,624 11/42 Holt 166--100 2,690,123 9/54 Kanady 166-352,965,176 12/60 Brieger 166-187 BENJAMIN HERSH, Primary Examiner.

NORMAN YUDKOFF, Examiner.

1. A METHOD FOR DETERMINING THE ALIGNMENT OF LATERAL PERMEABILITYVARIATIONS IN A FORMATION PENETRATED BY A BOREHOLE COMPRISING: SEALINGOFF A SECTION OF THE BOREHOLE INCLUDING AT LEAST A PORTION OF SAIDFORMATION; INJECTING A FLUID INTO THE SEALED OFF PORTION OF THEFORMATION IN CONTROLLED DIRECTIONS; DETECTING THE AZIMUTH OF THEDIRECTION IN WHICH THE FLUID IS INJECTED; ROTATING THE POINT AT WHICHTHE FLUID IS INJECTED IN INCREMENTS OF ABOUT 45* TO ATTEMPT INJECTIONAROUND THE ENTIRE PERIPHERY OF THE BOREHOLE AND RECORDING THE RATE OFINJECTION AND CORRESPONDING PRESSURE AS THE FLUID IS INJECTED IN EACHDIRECTION INCREMENT.